Page 26 - ITU-T Focus Group IMT-2020 Deliverables

2 ITU-T Focus Group IMT-2020 Deliverables

NOTE 1 – Local offloading can be used to support efficient traffic distribution. However, local offloading
requires a separate local mobile GW in existing IMT networks, which also brings up the needs to support
multiple APN connectivity in user devices or APN switching should be initiated, which may result in service
disruption of ongoing sessions and operational complexities.

NOTE 2 – Satellite networks can be used to off-load traffic from the terrestrial networks and, in particular,
for the video based traffic which is the largest contributor to the spectrum demands. This can be achieved
by traffic classification and intelligent routing and will thus reduce the demands on the terrestrial spectrum.
[REQ] The network architecture for IMT-2020 is required to reduce traffic of backhaul and core network.
NOTE – The heavily centralized architecture of existing IMT networks should be changed to cope with the
explosion of mobile data traffic. In IMT-2020 networks, therefore, gateways to an IMT-2020 core network
can be flexibly located closer to the cell sites, which will bring a significant reduction on backhaul and core
network traffic by enabling placing content servers closer to mobile devices and also be beneficial to the
latency of the services. The IMT-2020 core networks, therefore, is envisioned to be a distributed network
being composed of the multiple distributed gateways. The architectural changes expected from the
distributed network, including point-to-point access architecture between a UE and a service network in
existing IMT network, should be studied.

8.2 Enhanced massive machine type communication services
8.2.1 Description
In IMT-2020 networks, almost every object that can benefit from being connected is expected to be
connected through wired or wireless internet technologies, which will lead to a situation where the number
of connected devices exceeds the number of human user devices. These connected “things” can be various
ranging from low-complexity devices to highly complex and advanced devices. As more and more things get
connected, various services that utilize the connection capabilities of things will appear: smart energy
distribution grid system, agriculture, healthcare, vehicle-to-vehicle and vehicle-to-road infrastructure
communication.
At least one hundred thousand simultaneous active connections per square kilometre, which will be mostly
coming true by the deployment of those massive MTC (machine type communications) devices
(e.g., IoT/M2M devices), should be supported in IMT-2020 network. Consistent end-to-end user experience
should also be provided even in the presence of that large number of concurrent connections.

8.2.2 Requirements
[REQ] The network architecture for IMT-2020 is required to address architectural issues coming from the
massive number of MTC devices.
[REQ] The network architecture for IMT-2020 is required to prevent signalling and user data congestion by
massive number of MTC devices.
[REQ] The network architecture for IMT-2020 is required to provide signaling protocols to support various
traffic characteristics and communication types of MTC devices (for example, such as short or massive burst
traffic, delay sensitive or non-sensitive data, etc.).
[REQ] The network architecture for IMT-2020 is required to simplify the message procedures to prevent
signalling congestion and overload traffic.
NOTE – The traffic generated by a very large number of connected devices typically will be a relatively low
volume of non-delay-sensitive data; however, the traffic is characterized as intermittent short burst traffic.
The main problem in supporting the intermittent short burst traffic is that traffic has to go through the full
signaling procedure, which causes the waste of battery life, spectrum and network capacity. The
enhancement of current monolithic bearer management and the accompanied signaling in IMT-2020
network should be studied to cope with the issues coming from the increase of terminals.
[REQ] The network architecture for IMT-2020 is required to provide optimised user identification solution for
the massive IoT devices.

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